The letter, on the gold-embossed stationery with a swastika and Hitler's name, is dated "V-E Day" for May 8, 1945, and was written by Richard Helms to his then-3-year-old son, Dennis Helms, The Washington Post reports.
"Dear Dennis," the seven-sentence letter begins. "The man who might have written on this card once controlled Europe -- three short years ago when you were born. Today he is dead, his memory despised, his country in ruins."
The son, Dennis Helms, now a 69-year-old intellectual property lawyer in New Jersey, turned over the letter this year when the CIA contacted him and said it was redesigning its museum and was seeking memorabilia from Richard Helms.
Richard Helms had been a member of the Office of Strategic Services, the CIA's predecessor, when he wrote the letter and was a founding member of the CIA who became director in 1966. Former President Richard Nixon pushed him out in 1973, upset the CIA chief didn't help thwart the Watergate investigation, the Post said.
Of Hitler, the father wrote in the letter: "He had a thirst for power, a low opinion of man as an individual, and a fear of intellectual honesty. He was a force for evil in the world. His passing, his defeat -- a boon to mankind. But thousands died that it might be so."
The museum received the letter the day the world learned Osama bin Laden had been killed.
"When we got it, the hair on our arms stood up," said Toni Hiley, the CIA museum's curator. "Helms had such a sense of his own moment in history. The artifact itself would have made any museum professional's day. But the fact that we received it on the very day that we in the museum received news along with the rest of the world of the successful bin Laden operation stunned us."